The present invention relates to a laminated glass with an interlayer resinoid film containing functional ultra-fine particles dispersed therein and a method of producing this laminated glass.
There have been proposed colorless or colored architectural glasses having functions of heat insulation, ultraviolet ray insulation and improved radio wave transmission. Furthermore, there have been proposed automotive glasses having a function of heat insulation for insulating solar radiation energy incident on car interior and thus for lowering the air conditioning load, and a function of ultraviolet ray insulation. Recently, there has been an increasing demand for an architectural or automotive laminated glass having functions of heat insulation, ultraviolet ray insulation, and improved radio wave transmission, while this glass has a sufficient visible light transmittance.
There are several proposals that fine particles are contained in the interlayer film of laminated glass, for providing the laminated glass with a certain function(s). For example, Japanese Patent Unexamined Publication JP-A-2-22152 discloses an interlayer film of laminated glass, for insulating short wavelength light rays. This interlayer film is made of a plasticized polyvinyl butyral containing at least one light absorbing agent selected from special benzotriazole derivatives and an inorganic matter in the form of fine powder. 90% by weight of this inorganic matter has a particle diameter within a range from 250 to 400 nm. This interlayer film is characterized in that light rays of up to 400 nm wavelength is substantially insulated and that light rays of at least 450 nm wavelength is substantially transmitted therethrough. The light absorbing agent""s content is from 0.4 to 6 wt %, and the inorganic matter""s content is from 2 to 17 wt %.
As another example, Japanese Patent Unexamined Publication JP-A-4-160041 discloses an automotive window glass having a layer interposed between transparent platelike members. This layer is made of a mixture of a glass component and ultra-fine particles having an average diameter of up to 0.1 xcexcm. The glass component is an organic silicon or an organic silicon compound and serves to bond together at a relatively low temperature two glass plates of a laminated glass or an interlayer resinoid film and a glass plate. The ultra-fine particles has a function of transparent electric conductiveness, infrared reflection function, electromagnetic insulation function.
Japanese Patent Unexamined Publication JP-A-4-261842 discloses a laminated glass comprising an organic glass member, a transparent member, and an interlayer film interposed therebetween. This interlayer film contains 100 parts by weight of an ethylene-ethylacrylate copolymerized resin prepared by graft modification of a vinylsilane and 3-30 parts by weight of optional silicon dioxide fine particles. When the particle diameter of the fine particles is from 0.1 to 400 nm, scatter of light rays which are transmitted through the interlayer film can be prevented.
It is an object of the present invention to provide a laminated glass which has a good quality requisite for an architectural or automotive laminated glass itself and of which interlayer film has various additional functions such as heat insulation, ultraviolet ray absorption and the maintenance of a sufficient radio transmittance.
According to a first aspect of the present invention, there is provided a laminated glass comprising:
first and second transparent glass plates;
an interlayer film interposed between said first and second glass plates; and
functional ultra-fine particles which have a particle diameter of up to 0.2 xcexcm and are dispersed in said interlayer film.
According to a second aspect of the present invention, there is provided a method of producing a laminated glass, comprising the steps of:
(a) interposing an interlayer film between first and second glass plates, said interlayer film having functional ultra-fine particles which are dispersed therein and have a particle diameter of up to 0.2 xcexcm; and
(b) bonding together said first and second glass plates and said interlayer film.
As is mentioned above, a laminated glass according to the present invention has an interlayer film containing ultra-fine particles which have a particle diameter of up to 0.2 xcexcm and are dispersed in the interlayer film. With this, the laminated glass has various additional functions such as the provision of colorlessness or a certain desired color tone, heat insulation, ultraviolet ray insulation, the maintenance of a sufficient radio transmittance, and the like, without adding an adverse effect on the interlayer film""s basic characteristics requisite for an architectural or automotive laminated glass. Therefore, the laminated glass is capable of improving the air conditioning effect and inhabitability of automobile, building and the like, of reducing an adverse effect of ultraviolet rays on the interior of automobile, building or the like, and of maintaining a sufficient radio transmittance equivalent to that of a conventional float glass, for receiving and transmitting radio waves.
A laminated glass according to the present invention is well controlled in color tone, extremely low in haze value, and superior in transparency and in reduction of reflection and glare. For example, the laminated glass has requisite basic characteristics for an automotive safety glass. These basic characteristics are substantially equivalent to those of conventional automotive laminated glass and provide satisfactory results in various tests of Japanese Industrial Standard (JIS) R 3212 and the like.
In a method of producing a laminated glass according to the present invention, it is not necessary to use a glass plate having a special composition nor a glass plate having a special surface finish. A conventional production line for producing conventional laminated glasses can be used for producing a laminated glass of the present invention. Therefore, the laminated glass can be easily and economically produced. Furthermore, it can be flexibly produced according to the size and shape of the laminated glass.
In the following, a laminated glass according to the present invention will be described in detail. This laminated glass comprises first and second transparent glass plates and an interlayer film interposed therebetween. The interlayer film has functional ultra-fine particles which have a particle diameter of up to 0.2 xcexcm and are dispersed therein. These particles are used to provide various functions such as heat insulation, thereby maintaining the solar radiation transmittance within a range of up to 65%, while the scattering and reflection of the visible light rays is suppressed. In spite of the fact that the interlayer film contains the functional ultra-fine particles, it has been unexpectedly found that the laminated glass has an extremely low haze value, a good radio transmittance and a sufficient transparency and that the interlayer film is sufficient in bond strength against the first and second glass plates, in transparency, durability and the like. Even though the interlayer film contains the functional ultra-fine particles, the laminated glass can be produced in a production line for conventional laminated glasses. The functional ultra-fine particles have a particle diameter preferably up to 0.15 xcexcm or from 0.001 to 0.2 xcexcm, more preferably from 0.001 to 0.15 xcexcm or from 0.002 to 0.15 xcexcm, and still more, preferably from about 0.001 to about 0.10 xcexcm or from about 0.002 to about 0.10 xcexcm. It is preferable that these particles have a narrow particle diameter distribution, for example, within a range about 0.01 to about 0.03 xcexcm.
In the invention, it is preferable that the functional ultra-fine particles amount to up to 10.0 wt % based on the total weight of the interlayer film. With this, these particles have various functions such as heat insulation, for example, to maintain the solar radiation transmittance within a range of up to 65%, while a first condition that the laminated glass has an extremely low haze value, a sufficient radio transmittance and a sufficient transparency is satisfied, while a second condition that the interlayer film is sufficient in bond strength against the first and second glass plates, in transparency, durability and the like is satisfied, and while a third condition that the laminated glass can be produced by a production line for conventional laminated glasses is satisfied. If the amount of the functional ultra-fine particles exceeds 10.0 wt %, it becomes difficult to satisfy the above-mentioned first, second and third conditions. When the laminated glass is used as an architectural glass having a visible light transmittance (Tv) of at least 35%, it is necessary to add the ultra-fine particles made of inorganic pigment(s) in an amount within a range from about 0.1 to about 10 wt %. In general, in the production of the laminated glass as an architectural glass, the amount of the ultra-fine particles is preferably from about 0.01 to about 9 wt % and more preferably from about 0.05 to about 8 wt %. In general, in the production of the laminated glass as an automotive glass, the amount of these particles is preferably from about 0.01 to about 2.0 wt % and more preferably from about 0.1 to about 1.0 wt %. In conclusion, the amount of these particles is decided according to the balance between the above-mentioned additional functions of these particles and the basic characteristics of the laminated glass. That is, if the amount of these particles is too much, the additional functions of these particles become sufficient, but the basic characteristics of the laminated glass may be impaired. On the contrary, if the amount of these particles is too little, the basic characteristics of the laminated glass are maintained, but the additional functions of these particles become insufficient.
In the invention, the interlayer film is not limited to a particular material, but preferably made of a polyvinyl butyral (PVB) or an ethylene-vinylacetate copolymer (EVA), which is generally used as a material for the interlayer film. Examples of the material of the interlayer film are a plasticized PVB made by Sekisui Chemical Industries, Ltd., Monsant Japan, Ltd. or the like, an EVA made by Du pont Co. or Takeda Chemical Industries, Ltd. (DUMILAN (trade name)), and a modified EVA (e.g., MERUCENE G (trade name) made by Toso Co.). It is optional to add an additive(s) to the interlayer film, such as ultraviolet absorbing agent, antioxidant, antistatic agent, heat stabilization agent, lubricant, filler, coloring agent, and bond adjusting agent.
It is optional that the interlayer film according to the present invention is placed on a conventional interlayer film to prepare a laminate, and then this laminate is interposed between the first and second glass plates to prepare the laminated glass. Furthermore, it is optional that the interlayer film according to the present invention is interposed between first and second conventional interlayer films to prepare a laminate to be interposed between the first and second glass plates.
In the invention, it is preferable that the functional ultra-fine particles comprise at least one member selected from the group consisting of metals, compounds containing the metals; and composites containing the metals. These metals consist of Sn, Ti, Si, Zn, Zr, Fe, Al, Cr, Co, Ce, In, Ni, Ag, Cu, Pt, Mn, Ta, W, V and Mo. The compounds containing the metals consist of oxides of the metals, nitrides of the metals, oxynitrides of the metals, and sulfides of the metals. The composites containing the metals consist of the metals doped with at least one substance, and the compounds doped with the at least one substance. The at least one substance is selected from the group consisting of antimony, antimony compounds, fluorine, fluorine compounds, stannous compounds, and aluminum compounds. The functional ultra-fine particles may comprise a mixture of the above-mentioned at least one member and an organic resin. This mixture may be the at least one member coated with this organic resin.
Examples of the above-mentioned oxides of the metals for the functional ultra-fine particles are SnO2, TiO2, SiO2, ZrO2, ZnO, Fe2O3, Al2O3, FeO, Cr2O3, Co2O3, CeO2, In2O3, NiO, MnO and CuO. Exemplary commercial products of the functional ultra-fine particles made of TiO2are IT-S-UD (trade name) which is made by Idemitsu Petrochemical Co., Ltd. and has a particle diameter of 0.02 xcexcm, and UF01 (trade name) which is made by Tai Oxide Chemicals Co. and has a particle diameter of 0.018 xcexcm. An exemplary commercial product of the functional ultra-fine particles made of Fe2O3is NANOTITE (trade name) which is in the form of spherical ultra-fine hematite particles, has a particle diameter of 0.06 xcexcm and is made by Showa Denko K.K. Examples of the above-mentioned nitrides of the metals are TiN and AIN. An example of the above-mentioned sulfides of the metals is ZnS. Examples of the metals with doped with the at least one substance are SnO2doped with 9 wt % Sb2O3(ATO) made by Sumitomo Osaka Cement Co., SnO2 doped with fluorine, and SnO2 doped with 10 wt % Sb2O3. Examples of mixtures (composites) each containing at least two of the above-mentioned metals are In2O3xe2x88x925 wt % SnO2(ITO) made by Mitsubishi Material Co., and inorganic pigment ultra-fine particles such as Co2O3xe2x80x94Al2O3 (e.g., TM3410 (trade name) having a particle diameter from 0.01 to 0.02 xcexcm), TiO2xe2x80x94NiOxe2x80x94Co2O3xe2x80x94ZnO (e.g., TM3320 (trade name) having a particle diameter from 0.01 to 0.02 xcexcm) and Fe2O3xe2x80x94ZnOxe2x80x94Cr2O3 (e.g., TM3210 (trade name) having a particle diameter from 0.01 to 0.02 xcexcm). TM3410, TM3320 and TM3210 are made by Dai Nichi Seika Kogyo Co. Examples of the above-mentioned organic resin to be used together with the above-mentioned at least one member are fluorine compounds such as fluororesins, polytetrafluoroethylene (PTFE), LUBURON (trade name) made by Daikin Industries, Ltd., CEFRAL LUBE (trade name) of Central Glass Co., Ltd., and low molecular weight trifluoroethylene (TFE), silicone resins, silicone rubbers. Of the above examples, ATO and ITO are particularly preferable examples as the functional ultra-fine particles for an automotive laminated glass.
The above-mentioned organic resin is used to reduce bond strength between the PVB film and the first and second glass plates. In other words, in case that, for example, ATO or ITO is used as the functional ultra-fine particles, the bond strength may become too much. In this case, the organic resin is used to lower the pummel value and thus to reduce the bond strength to a permissible standard range. Thus, the purpose of the addition of the organic resin is similar to that of the primer coating on the glass plate surface or to that of the coating of the organic resin film made of fluororesin, silicone resin, silicone rubber or the like.
By the incorporation of the functional ultra-fine particles into the interlayer film, the laminated glass is provided with various functions such as heat insulation, ultraviolet ray insulation, the provision of colorlessness or a certain desired color tone, light insulation and the like.
In the invention, the interlayer may contain an organic ultraviolet-ray-absorbing agent. Examples of this agent are benzotriazole derivatives such as 2-(2xe2x80x2-hydroxy-5xe2x80x2-methylphenyl) benzotriazole, 2-(2xe2x80x2-hydroxy-3xe2x80x2,5xe2x80x2-ditert-butylphenyl) benzotriazole, 2-(2xe2x80x2-hydroxy-3xe2x80x2-tert-butyl-5xe2x80x2-methylphenyl)-5-chlorobenzotriazole, 2-(2xe2x80x2-hydroxy-3xe2x80x2,5xe2x80x2-ditert-butylphenyl)-5-chlorobenzotriazole and 2-(2xe2x80x2-hydroxy-3xe2x80x2,5xe2x80x2-ditert-amylphenyl) benzotriazole, benzophenone derivatives such as 2,4-dihydroxybenzophenone, 2-hydroxy-4-methoxy-benzophenone, 2-hydroxy-4-octoxybenzophenone, 2-hydroxy-4-dodecyloxybenzophenone, 2,2xe2x80x2-dihydroxy-4-methoxy-benzophenone, 2,2xe2x80x2-dihydroxy-4,4xe2x80x2-dimethoxybenzophenone and 2-hydroxy-4-methoxy-5-sulfobenzophenone, and cyanoacrylate derivatives such as 2-ethylhexyl-2-cyano-3,3xe2x80x2-diphenylacrylate and ethyl-2-cyano-3,3xe2x80x2-diphenylacrylate. An example of commercial products of the organic ultraviolet-ray-absorbing agent is TINUVIN327 (trade name) made by Ciba-Geigy Co.
In the invention, the interlayer film may contain an organic heat-absorbing agent(s). Examples of this agent are NIR-AM1 made by Teikoku Chemical Industries, Ltd., and as near infrared rays absorbing agents SIR-114, SIR-128, SIR-130, SIR-132, SIR169, SIR-103, PA-1001 and PA-1005 which are made by Mitsui Toatsu Chemicals, Inc. The interlayer film may further contain a pigment(s).
A laminated glass according to the present invention can be used as an architectural window glass or an automotive window glass such as a front windshield, a rear windshield with or without a shade band, a side windshield, or a sunroof.
In general, the sheet (surface) resistivity of a glass plate with glass antenna is preferably at least 20 kxcexa9/xe2x96xa1. In particular, when the glass plate is in contact with the antenna, the sheet resistivity is preferably at least 10 Mxcexa9/xe2x96xa1. If it is less than 10 Mxcexa9/xe2x96xa1, the difference between the sheet resistivity of a laminated glass and that of a glass plate itself may be at least 1 dB as an absolute value. The sheet resistivity of the laminated glass is preferably at least 15 Mxcexa9/xe2x96xa1 for maintaining this difference within 0.8 dB (absolute value). The sheet resistivity of the laminated glass is preferably within a range from about 20 Mxcexa9/xe2x96xa1 to about 10 Gxcexa9/xe2x96xa1 and more preferably within a range from about 22 Mxcexa9/xe2x96xa1 to about 10 Gxcexa9/xe2x96xa1 for obtaining a satisfactory radio wave transmittance, satisfactory optical characteristics and satisfactory physical and chemical characteristics.
In the invention, it is possible to obtain a laminated glass which is superior in radio wave transmittance, heat insulation, ultraviolet rays insulation and optical characteristics. This laminated glass is particularly suitable as an automotive windshield. In more detail, this laminated glass as an automotive windshield has a radio transmittance which is equivalent to that of a glass plate itself, a solar radiation transmittance of up to 65% thereby improving a so-called automotive inhabitability, a visible light transmittance of at least 65% or at least 70% thereby allowing the driver and a passenger(s) to have a good view, and a very low visible light reflectance thereby allowing the driver and a passenger(s) to have a good view, avoid misreading of traffic control signal and the like, and minimize the eye fatigue. As an automotive glass plate, it is preferable that the laminated glass has a visible light transmittance of at least 68 or 70%, a visible light reflectance of up to 14%, a solar radiation transmittance of up to 60%, and an excitation purity of up to 15 or 10%. As an architectural glass plate, it is preferable that the laminated glass has a visible light transmittance of at least 30%, a visible light reflectance of up to 20%, a solar radiation transmittance of up to 65%, and an excitation purity of up to 20%.
The arrangement of the interlayer film is flexible according to need. In other words, for example, the interlayer film may be sized and arranged such that the interlayer film is not formed on a position corresponding to the peripheral portion of the laminated glass, nor on a position corresponding to the feeding point(s), nor on a position corresponding to a portion on which a molding is formed, nor on a position corresponding to the whole or a part of the electric conductor portion of an antenna.
According to the invention, the interlayer film has a heat insulation characteristic and a high sheet-resistivity equivalent to that of a semiconductor film or of an insulating film. Therefore, the laminated glass of the invention does not cause radio disturbance in receiving AM radio waves, FM radio waves and the like, nor radio interference such as ghost image of the TV picture. Even in case that a film which has a high resistivity and a heat insulation characteristic is formed on a glass antenna device, the radio receiving capacity of the laminated glass is not be lowered.
The first and second glass plates of the laminated glass may be made of an organic glass or a composite glass of inorganic and organic materials and may be colorless or colored float glass plates. This colored float glass plates may have a color of green, bronze, gray or blue. The first and second glass plates may be flat or curved and used for a multiple glass, a by-layer glass, or the like. In general, it is preferable that the first and second glass plates have a thickness, for example, from about 1.0 mm to about 12 mm. For architectural use, these plates have a thickness preferably from about 2.0 mm to about 10 mm. For automotive use, these plates have a thickness preferably from about 1.5 mm to about 3.0 mm and more preferably from about 2.0 mm to about 2.5 mm.
In the following, a method of producing a laminated glass will be described in detail in accordance with the present invention. This method comprises the steps of:
(a) interposing an interlayer film between first and second glass plates, the interlayer film having functional ultra-fine particles which are dispersed therein and have a particle diameter of up to 0.2 xcexcm; and
(b) bonding together the first and second glass plates and the interlayer film.
It is preferable that the step (b) is conducted in an autoclave by a common autoclave method, or under reduced pressure for a period of time from 20 to 30 minutes, while an ambient temperature was raised from 80 to 120xc2x0 C. With this, the interlayer film will have uniformly uneven embossing thereon. However, in some cases, the step (b) may be conducted by one of various simpler methods.
In the following, a method of preparing the interlayer film will be described in detail in accordance with the present invention. This method comprises the steps of:
(c) dispersing up to 80.0 wt % of the functional ultra-fine particles in a plasticizer solution, based on the total weight of the plasticizer solution and the ultra-fine particles, so as to prepare a first mixture;
(d) adding up to 50 wt % of the first mixture to a PVB or to an EVA, based on the total weight of the PVB or EVA, so as to prepare a second mixture;
(e) optionally adding at least one additive to the second mixture so as to prepare a third mixture; and
(f) kneading the third mixture to uniformly disperse therein the functional ultra-fine particles, thereby to prepare a raw material of the interlayer film.
During the step (c), the functional ultra-fine particles can be well uniformly dispersed in the plasticizer solution. Therefore, the first mixture becomes superior in transparency. During the step (c), if the amount of the functional ultra-fine particles exceeds 80.0 wt %, it becomes difficult to get uniformly dispersed ultra-fine particles. The amount of the ultra-fine particles is preferably up to about 20.0 wt %, more preferably up to about 10.0 wt %, and still more preferably within a range from 0.5 to 5.0 wt %. If the amount of the ultra-fine particles is too small, the advantageous effect of the addition may become insufficient.
During the step (d), if the amount of the first mixture exceeds 50 wt %, the ultra-fine particles may not be uniformly dispersed in the PVB or the EVA, and the interlayer film""s basic characteristics may become unsatisfactory. During the step (d), the amount of the first mixture is preferably up to about 45 wt % and more preferably within a range from about 10 wt % to about 40 wt %. During the step (f), the third mixture is kneaded by a common mixer, Banbury mixer, Brabender plastograph, a kneader, or the like.
Examples of the plasticizer are phthalic acid esters such as dioctyl phthalate (DOP), diisodecyl phthalate (DIDP), ditridecyl phthalate and butylbenzyl phthalate (BBP), phosphoric acid esters such as tricresyl phosphate (TCP) and trioctyl phosphate (TOP), fatty acid esters such as tributyl citrate and methylacetyl ricinolate (MAR), polyether esters such as triethyleneglycol-di-2-ethylbutylate (3GH) and tetraethyleneglycoldihexanol, and mixtures of these compounds.
Examples of solvents for dissolving therein a PVB are ethyl alcohol, n-propyl alcohol, isopropyl alcohol, n-butyl alcohol and methylene chloride. Examples of solvents for dissolving therein an EVA are toluene, xylene and methylene chloride.
After the step (f), the raw material is shaped into the interlayer film using a common extruder, a calender or the like. The thickness of the interlayer film is preferably from about 0.2 to about 1.2 mm and more preferably from about 0.3 to about 0.9 mm.
There is provided an alternative method of preparing the interlayer film according to the present invention. This alternative method comprises the steps of:
(c) uniformly dispersing the functional ultra-fine particles having a particle diameter within a range from 0.001 to 0.2 xcexcm, in a solvent which is capable of dissolving therein a PVB or an EVA, so that a first mixture is prepared;
(d) adding the PVB or the EVA, an optional plasticizer and at least one other optional additive to the first mixture, so that a second mixture in which the PVB or the EVA is dissolved is prepared;
(e) kneading the second mixture;
(f) shaping the kneaded second mixture into a wet film; and
(g) drying the wet film at a temperature from 50 to 110xc2x0 C. into the interlayer film.
There is provided a further alternative method of preparing the interlayer film in accordance with the present invention. This further alternative method comprises the steps of:
(c) heating a PVB or an EVA at a temperature which is higher than a glass transition temperature thereof, the glass transition temperature being within a range from 55 to 90xc2x0 C., so that the PVB or the EVA is softened; and
(d) adding functional ultra-fine particles having a particle diameter from 0.001 to 0.2 xcexcm to the softened PVB or EVA, so that a first mixture is prepared; and
(e) kneading the first mixture so as to uniformly disperse therein the functional ultra-fine particles, thereby preparing the raw material of the interlayer film.
The following examples are illustrative of the present invention, but these examples are not limitative.